In vending machines, especially for frozen products, the main elements that draw the attention of the constructors of these machines are the solutions of grippers that pick the product from the refrigeration chamber.
In the prior art, both mechanical grippers and pneumatic grippers are known. Mechanical ones are described inter alia in the patent application EP2871617 relating to a vending machine for frozen products. In that vending machine, the product gripper is composed of four serrated arms mounted in the head, which, thanks to the serrated arms, snap into the lid on the box by the lowering action. Although this solution is very practical for frozen products packed in plastic boxes with a lid, it can not unfortunately be used for other types of packaging.
For products with less regular shape or for products packed in a different way than a box with a cover, solutions are sought which include vacuum/pneumatic suction devices allowing vacuum extraction of products from e.g. fridges or freezers.
Among others, the U.S. Patent Application No. 2004/0050852 discloses a vending machine for Fastcorp products, which employs vacuum grippers. The principle of operation of this solution is that once the product selection signal is received, an electric actuator opens the freezer compartment lid to the upright position and a carriage with the gripper moves and takes a position over the selected product. A suction pump is started and lowered on a supply line ended with a suction cup. When the product is touched, a pressure sensor causes the pump to rise with the product and the carriage travels out of the cooling chamber to the supply trough—in the position above the supply trough. Then the suction pump is switched off, the solenoid valve which removes vacuum is opened, the product falls into the supply trough and the electric actuator closes the lid of the refrigerating chamber.
The disadvantage of this solution is the large size pump lowered onto the supply line to the inside of the product chamber. The pump diameter of approx. 65 mm requires chambers of a similar cross-section and prevents picking up products of small dimensions.